双时基频率校准电路

提供精确的时间基准是精密仪器和高精度设备计时和工作的关键技术之一。文中采用两套晶振电路，通过分频产生高频和低频两个频率信号，采用编码的方法对两个频率信号在每一个时钟周期内进行动态校核，只有两个晶振的频率在允许的精度范围内，或同时增大（缩小）相同的倍数，校核后频率信号才是正确的，且能给系统提供精确的时间基准。该方法能有效防止系统的时钟周期因意外的原因伸长或缩短。整个电路可以作为精密仪器或高精度设备的一个模块电路。

Dual Time Bases Frequency Correctory Circuit

Supplying accurate time base is one key tecnology which exact instruments and high accurate devices work.This paper adopts two sets of crystal circuits,via debasing frequency to produce a high frequency and a low frequency signals,and coding for the two frequency signals to adjust in every period.Only if their precisions are in area of permission,or advancing (debasing) same multiple,this frequency is right and supply accurate time base for system.This method effectively prevents protraction of shorten of system clock.The whole circuit can become a module circuit of exact instruments and hign accurate devices.